Process and apparatus for polishing plate glass



July 29, l930. H, K, HITCHCOCK 1,771,408

PROCESS AND APPARATUS FOR POLISHING PLATE GLASS Original Filed OG'. 29, 1923 4 Sheets-Sheet l July 29, 1930., H. K. HITCHCOCK I,771,408

PROCESS AND APPAATUS -FOR POLI-SHING PLATE GLASS original Filed oct. 29, 1923 4 sheets-sheet 2 INVENTOR July 29, 1930. Y

H. K. HITCHCOCK 1,771,408

PROCESS AND APPARATUS FOR POLISHING PLATE GLASS A 6 y Y 9g ,9 gk

si o Il" i: L l' x l' 7 9 wI 5l* July 2g, 1930. H, KfHlTCHCOCK 1,771,408

PROCESS AND APPARATUS FOR POLISHING PLATE GLASS Original Filed Oct. 29, 1925 4 Sheets-Sheet 4 INVENTOR Parente-a ,July-` zs, 193e UNITED' STATES, PATENT OFFICE H ALBERT x. HITcH'cocx, or PITTSBURGH,

PENNSYLVANIA, AssIeNon To PITTSBURGH rLATa eLAss COMPANY, A conrozaATIoN or rENNsYLvANrA rnocnss AND rrAaATUs ron roLrsnINe PLATE GnAss original application met october sa, .1923, semi No.

1928. Serialparatus for polishing glass, the present ap- 1 in s, wherein:

. mounted the spi 'plication constituting a division ofv m application, Serial No. 671,374. It is designed for use in connection with the so-called straight-away surfacing operation and has for its primary objects, the rovis'ion of a process and apparatus where the cons1stency 'of the rou e mixture is varied the length of travel of ytie glassA to be polished, and whereby the felts are satisfactorily cleaned without interfering with or interrupting the polishing operation. One form of the apparatus is shown in the accompanying drawlgure 1 is a vertical section through one form of apparatus. Fig. 2 is a plan view of lthe apparatus of Fig: 1. Fig. 3 is a section on the line III-III of Fig. '1. Fig. 4 is a vertical section through a modified formv of the apparatus. Fig.5 is a plan view 'of the apparatus of Fig. 4. And Fig. 6- is a dlagrammatic side elevation, view partially in.

section showing the method of circulating and mixing the rouge and water.

Referring to the construction of Figs. 1, 2 and 3, 1 is the sindle housing in whlch is the lowerend of the housing and. is secured to the runner frame 3 by means of the key 4. The runner frame is preferably a steel castin I of the skgletonl form indicated in 2 an carries fi `e runner blocks 5, although t p is number may be varied to suit requirements,

it being preferred, however, to,use runner blocks of relatively large diameter as comared with those-ordinari] used so'that a ess number are used than 1f smaller runner blocks werev emplo ed.

.The runner bloc s are of annular form,'as indicated in Fig. 1 and carry u on their lower sides the annular discs 6 of fe t or other yielding material suitable for use with rouge or' other polishing material, such feltbeing preferably secured to the runner blocks by means of water proof cement. The runner blocks are provided with hollow shafts 7 which are secured to such blocks by means of rubber diaphragms .8 clamped at their inner edges to the flanges of theshaftsby means le 2 which projects from 671,374. mvida and No. 265,147.

of the collars 9 held in place by screws or bolts and at their outer edges by means of the collars 10 held in place by the bolts 11. The shafts are journaled in the bearings 12, provided with suitable bushin s, and disengagei ment o f the shafts from t e bearings, when `the runner frame is raised, is prevented by means of the ca s 13 which are-screwed down into the ends o the shafts as indicated at`14. Thel perforations 1'5-,throu h the centers of the shafts provide conduits or the passageofv a polishing mixture to the spaces at the cen'- this application med April 7, .I

ters of the blocks, and the dia hragms 8 prevent any splashing or loss. o mixture. f

' Mounted upon the top of the runnerframe is a casting 16 provided with the five annular troughs 17, 18, 19, 20 and 21 which communicate with the passages 15 through the runner the polishing block shafts by means of the pipes 22, 23, 24,

and 26. These annular troughsare s u plied from the container 27 by means o f t e pipes 28, 29, 3 0, 31 and 32. Secured in 'fixed position in the container 27 isa transverse box 33 divided up into live compartments 34, 35, 36, 37 and 38, each of which communicates with one ,of the pipes as.

indicated in Fig. 3 which showsthe connection of the compartment 36 with the pipe 30. The compartments are supplied intermittently with the rouge mixture 1n `the container 27 by means of the wheel 39 mounted for rotation and provided withth'e five buckets 40, 41, 42, 43 and 44 mounted tov the rods 45 extending between the sides of the wheel, these'buckets being arranged in different vertical y 4 plies one ofthe compartments 34, 35, 36, 37 and 38. The swinging'movement of the buckets in one direction 1s stopped by means of the stop members 46 on the periphery of the swing freely onV planes, so that each one supwheel, so that upon the rotation of the wheel inthe direction indicated by the arrow in Fig. 1, each bucketscoops u a quantity of the polishing mixture, and-w en it arrives at .the position of the-.bucket 42 in Fig. 1, the

the .box 33.

The container 27 -is sup lied with a mixture 'contents-is-dumped into a compartment in rouge and water are supplied to the tank and the mixture is kept agitatedrand thoroughly mixed by means of paddles 54 carried by the shaft 55, such shaft being driven by the belt 56 -passing around a pulley 57 on the upper end of the shaft, or by any other suitable means Leading from the main 51 are the spigots 47 which go to the various polishing machines. mixing insures that the water and rouge will be thoroughly mixed and that the mixture furnished to all of the polishing machines through the spigots 47 will be the same. The

main 51 is preferably made of wood as are,

also the spigots 47 in order to resist the action of the rouge composition, which is acid in character, although corrosion resisting lmetal might be used. The 'main is preferably carried along over the various machines so that thespigots can discharge directly into the containers 27. There is thus little danger of the mixture clogging in its-passage from `the main to the container, and if this occurs,

the diiliculty may be quickly removed by removing the spigot and inserting a new one. The wheel 39 is driven from the countershaft 58 by means of the belt 59 (Fig. 3), the step pulleys 60 and 61 being employed so that the speed of rotation of the wheel may beregulated to give any desired interval of (feed and' to regulate the amount of feed. The amount of feed may also be variedby varying the level of the liquid in the container 27.

As indicated in Fig. 2, the glass sheet 62 which is being polished is carried upon a table or car 63, and the width of the lass is Lhan bloc s which, in a continuous operation suchl such that the runner blocks overhang t e edge of the glass when the runners are in their` side positions. Thisv arrangement of overprovides a means for cleaning the as this, would otherwise cake up with rouge and with particles of glass and become ineffective in the course of time. By means of the feed arrangement as heretofore described, a mixture of rouge and ywater is` supplied to each runner at se arated intervals, and when a .discharge o this mixture occurs to a runner block, its surface is so softened that the rouge is readily scraped off as the runner asses over the edges ofthe glass-sheet. T einterval of feed is so ar- This method of circulation andranged that this cleaning effect is secured -only when necessary so that the rouge is not scraped olf before it has had an opportunity to do the amount of polishing work which 1t should do. If it is necessary to give the felts a more thorough cleaning than is afforded by the intermittent discharge of rouge and water, this may be accomplished b diluting the mixture in the container 2 so that it is very thin or by using only Water in the container for a short time.

The discharge of the rouge mixturev to the centers of the runners is advantageous, since there is no waste and the rouge in order to escape from beneath the felt must pass between the felt and the glass. The annular felt thus acts somewhat as a brush distributing the rouge mixture over the surface of the glass so that there is a minimum amount of waste incident to the mixture flowing oil' of the side of the table.

This feature and the supplying of the rouge beneath the dial the bearings and other parts from the `cor roding action of the rouge mixture. In this connection, the hollow shafts 7 are preferably made of some acid resisting composition so that they will last for a long period despite the corroding action vof the rouge mixture.

lThe method of feed, including the arrangement illustrated in Fig. 6 is also of advantage since it permits all of the machines of a series to be fed from the container or tank 50. The various machines of a series require a mixture containing a less and less proportion of rouge as the polishing progresses, and this condition may be readily secured in the apparatus as abovedescribed by supplying a rouge mixture of the same character to all of the containers 27 by means ofthe spigots 47K and then utilizing the water pipes 48 to dilute the-mixture to the proper consistency for the particular polishing stage for which the machine is being used. y

If desired, the excess water to give the lnecessary dilution may be suppliedv tothe ishing felts are of relatively large volume somewhat in excess of that required for polishing and well spaced apart in period of time, so that each time the mixture is applied, the felts are well soaked throughout, resulting in the washing away or loosening of used rouge, which tends to become caked on the surfaces of the felts, so that the formation of a relatively hard surface is avoided. This is desirable, as any hard particles caught by manana the felts will scratch the glass if the surfaces of the felts are hard and glazed, but will not do soif the surfaces are relatively soft as the hard particles will sink into the soft surface. lin intermittent polishing operation, the for mation of the hard glazed surfaces are avoided by applying quantities of water either at the beginning or end of the operation, but this is not feasible in a continuous operation, as the` application of water alone at intervals sucient to clean the felts would result in an underpolish of-that portion of the glass assing beneath the polishers at the time the water is applied. The present procedure of applying the rouge mixture at intervals in relatively large volumes keeps the rouge coating on the felts soft, so that `it is vnot necessary to remove and clean them. The old rouge is either washed oil' by the volumes of mixture or else so loosened that it becomes detached, and a fresh, relatively soft coating or surface is reestab lished. v

Figs. 4 and 5 illustrate a modification, such modication relating to the runner block construction andthe method of supplying the v rou e mixture from the annular troughs to the runner frame 72 by means of the bolt the locks, the other parts of the apparatus being the same as described in connect-ion with the apparatus of Figs. l to 3, and being similarly` numbered. In this type of con struction, the runner block 64 is provided with an annular clamp 65 held by the bolts 66, and between thisclamp and the block is secured a rubber diaphragm 67 corresponding to the diaphragms 8 of Fig. 1, but provided with perforations 68, the inner edge of the diaphra being clamped to the sleeve 69 by means o the bolts 70. The upper end of the sleeve 69 is threaded to a cap 71 and this cap is secured against the lower side of -73 which has a collar or shoulder 74 fitting between the top of the sleeve 69 and the flange on the cap 71. The lower portion of the bolt 73 acts as a s indle or plvot, the sleeve 69 serving as the earing therefor. The clamp 65 is provided with a s 4lash wall 75 and the space inside of this wal is fed with a rouge mixture from the pipe 76 leading from one r of the annular trou hs or grooves 77, such troughs or grooves eing fed b means of the pipes 78 corresponding to t e pipes 28 to 32 of the Fig. 1 construction. In this construction asin that of Fi'g. 1, the dia hra which connects the runner block to t e sp1ndle is relatively flexible so that the runner block can adjust itself to the surface of the glass. Also in this construction as in thatof Fig. 1, the lower ends of the pipes leading to the annular. troughs are supported by means of a bracket 79 clamped around the lower Vend of the spindle housing.

WhatIclaim is: i 1. Process of supplying a polishing mix- -rouge caked on the felts and then to rees! tablish a new coating on the felts from the mixture thus supplied'.

2. Apparatus for supplying a polishing mixture to a plurality of polishing machines arranged in series for a straight away oper ation, which comprises a container for a mixture of polishing material and water, means forA agitating the mixture, means for continuously circulating the mixture through a conduit extending along the series of machines and returnin to said container, means for withdrawing t e mixture from a plurality of oints along the conduit, means for diluting t e mixture drawn from said points to varying degrees of density, and means for supplying the mixtures to the successive polishing machines, the mixture of greater density being supplied to the first of the series of machines, and the mixtures of less and less density to the succeeding machines.

In testimony whereof, I have hereunto subscribed my name this 13th day of March,

lees.

n. x. HITCHCOCK.

ioo 

